Body elongation and placentome evolution in the scincid lizard genus Chalcides (Squamata, Scincidae)

This paper examines the differences in body morphology, clutch size and viv iparity between relatively elongated and non-elongated species of Chalcides . Reduction in egg size and placentome development in snake-like species se em to be necessary consequences of evolutionary body attenuation in this gr oup of skinks. In particular, the elliptic placenta might have evolved to m aintain adequate clutch size by compensating for yolk mass reduction.